Bearings have been made with polymeric materials. In industrial applications bearings sometimes function in hostile environments of heat and vibration. Suitable bearing materials for use in such hostile environments are restricted to thermoset polymers which must be processed by casting or machining. The use of a casting or machining process is time consuming and can be carried out only at high manufacturing cost. Therefore, the process is not suitable for large volume, low cost industrial applications.
Others have attempted the use of thermoplastic polymeric materials in the making of plastic bearings. The heat generated in the operation of a bearing causes many problems for a thermoplastic bearing, including thermal distortion and loss of dimensions. To solve these problems, others have designed plastic bearings with a molded-in metal structural enforcement. For example, one known bearing includes a polymeric matrix material used as a coating on a steel mesh frame. The steel mesh frame provides the structural integrity of the bearing while the polymeric matrix material provides the desirable frictional properties of the sliding surface. Unfortunately, the method required to produce such a bearing is labor intensive and requires complicated processing steps. Therefore, it is not suitable for low cost, high volume industrial applications.
In view of the shortcomings of the prior art, it is desirable to provide a polymeric based composite bearing that can be injection molded of a thermoplastic material, with improved strength and frictional properties, and that can be produced in a low cost, high volume industrial process. It is also desirable that such a bearing be injection molded of a homogeneous material and not require a metal enforcement for structural support.